Pen



FIG. 1 is a perspective view of a pen showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof; the left side elevational view is a mirror image of the right side;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken lines showing the cap, the rear portion of the barrel, and the conical portion of the pen from which the writing tip of the pen extends, as well as a series of diagonal striations on the grip of the claimed design, illustrate environmental matter and form no part of the claimed design. 

The ornamental design for a pen, as shown and described. 